The compounds of the instant invention are adenosine analogs having some of the same activity as adenosine, but having a significantly longer duration of action. A distinguishing feature of these compounds from other adenosine analogs previously described, is the discovery that N.sup.6 -tricyclicalkyl adenosines have favourable ratio of affinities at A1 and A2 receptors and highly desirable central nervous system and cardiovascular activities, such as antipsychotic, sedative, or antihypertensive.